298 lines
9.7 KiB
C++
298 lines
9.7 KiB
C++
/* OctoWS2811 - High Performance WS2811 LED Display Library
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http://www.pjrc.com/teensy/td_libs_OctoWS2811.html
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Copyright (c) 2013 Paul Stoffregen, PJRC.COM, LLC
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Permission is hereby granted, free of charge, to any person obtaining a copy
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of this software and associated documentation files (the "Software"), to deal
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in the Software without restriction, including without limitation the rights
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to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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copies of the Software, and to permit persons to whom the Software is
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furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be included in
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all copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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THE SOFTWARE.
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*/
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#include <string.h>
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#include "OctoWS2811.h"
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uint16_t OctoWS2811::stripLen;
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void * OctoWS2811::frameBuffer;
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void * OctoWS2811::drawBuffer;
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uint8_t OctoWS2811::params;
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DMAChannel OctoWS2811::dma1;
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DMAChannel OctoWS2811::dma2;
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DMAChannel OctoWS2811::dma3;
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static const uint8_t ones = 0xFF;
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static volatile uint8_t update_in_progress = 0;
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static uint32_t update_completed_at = 0;
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OctoWS2811::OctoWS2811()
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{
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// Unusable
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}
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void OctoWS2811::attach(uint32_t numPerStrip, void *frameBuf, void *drawBuf, uint8_t config)
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{
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stripLen = numPerStrip;
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frameBuffer = frameBuf;
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drawBuffer = drawBuf;
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params = config;
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}
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// Waveform timing: these set the high time for a 0 and 1 bit, as a fraction of
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// the total 800 kHz or 400 kHz clock cycle. The scale is 0 to 255. The Worldsemi
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// datasheet seems T1H should be 600 ns of a 1250 ns cycle, or 48%. That may
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// erroneous information? Other sources reason the chip actually samples the
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// line close to the center of each bit time, so T1H should be 80% if TOH is 20%.
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// The chips appear to work based on a simple one-shot delay triggered by the
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// rising edge. At least 1 chip tested retransmits 0 as a 330 ns pulse (26%) and
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// a 1 as a 660 ns pulse (53%). Perhaps it's actually sampling near 500 ns?
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// There doesn't seem to be any advantage to making T1H less, as long as there
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// is sufficient low time before the end of the cycle, so the next rising edge
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// can be detected. T0H has been lengthened slightly, because the pulse can
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// narrow if the DMA controller has extra latency during bus arbitration. If you
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// have an insight about tuning these parameters AND you have actually tested on
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// real LED strips, please contact paul@pjrc.com. Please do not email based only
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// on reading the datasheets and purely theoretical analysis.
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#define WS2811_TIMING_T0H 60
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#define WS2811_TIMING_T1H 176
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// Discussion about timing and flicker & color shift issues:
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// http://forum.pjrc.com/threads/23877-WS2812B-compatible-with-OctoWS2811-library?p=38190&viewfull=1#post38190
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void OctoWS2811::begin(void)
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{
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uint32_t bufsize, frequency;
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bufsize = stripLen*24;
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// set up the buffers
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memset(frameBuffer, 0, bufsize);
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if (drawBuffer) {
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memset(drawBuffer, 0, bufsize);
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} else {
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drawBuffer = frameBuffer;
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}
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// configure the 8 output pins
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GPIOD_PCOR = 0xFF;
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pinMode(2, OUTPUT); // strip #1
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pinMode(14, OUTPUT); // strip #2
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pinMode(7, OUTPUT); // strip #3
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pinMode(8, OUTPUT); // strip #4
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pinMode(6, OUTPUT); // strip #5
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pinMode(20, OUTPUT); // strip #6
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pinMode(21, OUTPUT); // strip #7
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pinMode(5, OUTPUT); // strip #8
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// create the two waveforms for WS2811 low and high bits
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frequency = (params & WS2811_400kHz) ? 400000 : 800000;
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analogWriteResolution(8);
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analogWriteFrequency(3, frequency);
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analogWriteFrequency(4, frequency);
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analogWrite(3, WS2811_TIMING_T0H);
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analogWrite(4, WS2811_TIMING_T1H);
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// pin 16 triggers DMA(port B) on rising edge (configure for pin 3's waveform)
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CORE_PIN16_CONFIG = PORT_PCR_IRQC(1)|PORT_PCR_MUX(3);
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pinMode(3, INPUT_PULLUP); // pin 3 no longer needed
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// pin 15 triggers DMA(port C) on falling edge of low duty waveform
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// pin 15 and 16 must be connected by the user: 16 is output, 15 is input
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pinMode(15, INPUT);
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CORE_PIN15_CONFIG = PORT_PCR_IRQC(2)|PORT_PCR_MUX(1);
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// pin 4 triggers DMA(port A) on falling edge of high duty waveform
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CORE_PIN4_CONFIG = PORT_PCR_IRQC(2)|PORT_PCR_MUX(3);
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// DMA channel #1 sets WS2811 high at the beginning of each cycle
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dma1.TCD->SADDR = &ones;
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dma1.TCD->SOFF = 0;
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dma1.TCD->ATTR = DMA_TCD_ATTR_SSIZE(0) | DMA_TCD_ATTR_DSIZE(0);
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dma1.TCD->NBYTES_MLNO = 1;
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dma1.TCD->SLAST = 0;
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dma1.TCD->DADDR = &GPIOD_PSOR;
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dma1.TCD->DOFF = 0;
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dma1.TCD->CITER_ELINKNO = bufsize;
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dma1.TCD->DLASTSGA = 0;
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dma1.TCD->CSR = DMA_TCD_CSR_DREQ;
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dma1.TCD->BITER_ELINKNO = bufsize;
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// DMA channel #2 writes the pixel data at 20% of the cycle
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dma2.TCD->SADDR = frameBuffer;
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dma2.TCD->SOFF = 1;
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dma2.TCD->ATTR = DMA_TCD_ATTR_SSIZE(0) | DMA_TCD_ATTR_DSIZE(0);
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dma2.TCD->NBYTES_MLNO = 1;
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dma2.TCD->SLAST = -bufsize;
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dma2.TCD->DADDR = &GPIOD_PDOR;
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dma2.TCD->DOFF = 0;
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dma2.TCD->CITER_ELINKNO = bufsize;
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dma2.TCD->DLASTSGA = 0;
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dma2.TCD->CSR = DMA_TCD_CSR_DREQ;
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dma2.TCD->BITER_ELINKNO = bufsize;
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// DMA channel #3 clear all the pins low at 48% of the cycle
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dma3.TCD->SADDR = &ones;
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dma3.TCD->SOFF = 0;
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dma3.TCD->ATTR = DMA_TCD_ATTR_SSIZE(0) | DMA_TCD_ATTR_DSIZE(0);
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dma3.TCD->NBYTES_MLNO = 1;
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dma3.TCD->SLAST = 0;
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dma3.TCD->DADDR = &GPIOD_PCOR;
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dma3.TCD->DOFF = 0;
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dma3.TCD->CITER_ELINKNO = bufsize;
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dma3.TCD->DLASTSGA = 0;
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dma3.TCD->CSR = DMA_TCD_CSR_DREQ | DMA_TCD_CSR_INTMAJOR;
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dma3.TCD->BITER_ELINKNO = bufsize;
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#ifdef __MK20DX256__
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MCM_CR = MCM_CR_SRAMLAP(1) | MCM_CR_SRAMUAP(0);
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AXBS_PRS0 = 0x1032;
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#endif
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// route the edge detect interrupts to trigger the 3 channels
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dma1.triggerAtHardwareEvent(DMAMUX_SOURCE_PORTB);
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dma2.triggerAtHardwareEvent(DMAMUX_SOURCE_PORTC);
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dma3.triggerAtHardwareEvent(DMAMUX_SOURCE_PORTA);
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// enable a done interrupts when channel #3 completes
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dma3.attachInterrupt(isr);
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//pinMode(1, OUTPUT); // testing: oscilloscope trigger
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}
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void OctoWS2811::isr(void)
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{
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dma3.clearInterrupt();
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update_completed_at = micros();
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update_in_progress = 0;
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}
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int OctoWS2811::busy(void)
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{
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//if (DMA_ERQ & 0xE) return 1;
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if (update_in_progress) return 1;
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// busy for 50 us after the done interrupt, for WS2811 reset
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if (micros() - update_completed_at < 50) return 1;
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return 0;
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}
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void OctoWS2811::show(void)
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{
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uint32_t cv, sc;
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// wait for any prior DMA operation
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while (update_in_progress) ;
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// it's ok to copy the drawing buffer to the frame buffer
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// during the 50us WS2811 reset time
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if (drawBuffer != frameBuffer) {
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// TODO: this could be faster with DMA, especially if the
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// buffers are 32 bit aligned... but does it matter?
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memcpy(frameBuffer, drawBuffer, stripLen * 24);
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}
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// wait for WS2811 reset
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while (micros() - update_completed_at < 50) ;
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// ok to start, but we must be very careful to begin
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// without any prior 3 x 800kHz DMA requests pending
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sc = FTM1_SC;
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cv = FTM1_C1V;
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noInterrupts();
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// CAUTION: this code is timing critical. Any editing should be
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// tested by verifying the oscilloscope trigger pulse at the end
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// always occurs while both waveforms are still low. Simply
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// counting CPU cycles does not take into account other complex
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// factors, like flash cache misses and bus arbitration from USB
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// or other DMA. Testing should be done with the oscilloscope
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// display set at infinite persistence and a variety of other I/O
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// performed to create realistic bus usage. Even then, you really
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// should not mess with this timing critical code!
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update_in_progress = 1;
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while (FTM1_CNT <= cv) ;
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while (FTM1_CNT > cv) ; // wait for beginning of an 800 kHz cycle
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while (FTM1_CNT < cv) ;
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FTM1_SC = sc & 0xE7; // stop FTM1 timer (hopefully before it rolls over)
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//digitalWriteFast(1, HIGH); // oscilloscope trigger
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PORTB_ISFR = (1<<0); // clear any prior rising edge
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PORTC_ISFR = (1<<0); // clear any prior low duty falling edge
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PORTA_ISFR = (1<<13); // clear any prior high duty falling edge
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dma1.enable();
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dma2.enable(); // enable all 3 DMA channels
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dma3.enable();
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FTM1_SC = sc; // restart FTM1 timer
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//digitalWriteFast(1, LOW);
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interrupts();
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}
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void OctoWS2811::setPixel(uint32_t num, int color)
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{
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uint32_t strip, offset, mask;
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uint8_t bit, *p;
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switch (params & 7) {
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case WS2811_RBG:
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color = (color&0xFF0000) | ((color<<8)&0x00FF00) | ((color>>8)&0x0000FF);
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break;
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case WS2811_GRB:
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color = ((color<<8)&0xFF0000) | ((color>>8)&0x00FF00) | (color&0x0000FF);
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break;
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case WS2811_GBR:
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color = ((color<<8)&0xFFFF00) | ((color>>16)&0x0000FF);
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break;
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default:
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break;
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}
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strip = num / stripLen; // Cortex-M4 has 2 cycle unsigned divide :-)
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offset = num % stripLen;
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bit = (1<<strip);
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p = ((uint8_t *)drawBuffer) + offset * 24;
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for (mask = (1<<23) ; mask ; mask >>= 1) {
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if (color & mask) {
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*p++ |= bit;
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} else {
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*p++ &= ~bit;
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}
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}
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}
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int OctoWS2811::getPixel(uint32_t num)
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{
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uint32_t strip, offset, mask;
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uint8_t bit, *p;
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int color=0;
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strip = num / stripLen;
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offset = num % stripLen;
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bit = (1<<strip);
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p = ((uint8_t *)drawBuffer) + offset * 24;
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for (mask = (1<<23) ; mask ; mask >>= 1) {
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if (*p++ & bit) color |= mask;
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}
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switch (params & 7) {
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case WS2811_RBG:
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color = (color&0xFF0000) | ((color<<8)&0x00FF00) | ((color>>8)&0x0000FF);
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break;
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case WS2811_GRB:
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color = ((color<<8)&0xFF0000) | ((color>>8)&0x00FF00) | (color&0x0000FF);
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break;
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case WS2811_GBR:
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color = ((color<<8)&0xFFFF00) | ((color>>16)&0x0000FF);
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break;
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default:
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break;
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}
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return color;
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}
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